This invention concerns a method for providing dimensionally stable absorbent bodies which comprise compressed cellulosic fibers. In particular, the invention concerns a method for compressing such bodies, in the form of cylindrical tampons, to insure against unwanted expansion after compression.
Absorbent, cylindrical tampons are now widely used for a number of absorbent purposes in the medical and dental field but are primarily used in the field of feminine hygiene as catamenial tampons. In this latter field, there are two basic types: digitally inserted tampons, inserted with the fingers, and applicator tampons, inserted with the aid of an applicator. Both types are usually made by folding or rolling a loosely associated, rectangular strip of absorbent material, usually fibrous and cellulosic in nature, into a blank and then compressing the blank into a cylindrically shaped product. In the case of digital tampons, the product is then wrapped and packaged and, in the case of applicator tampons, the product is first inserted into the applicator and then wrapped and packaged.
In both instances it is, of course, highly desirable that the tampon maintains its final compressed shape. Unfortunately, however, it has been found that after processing and even after packaging, the compressed absorbent material making up the tampon has a tendency to expand, first to a large degree just after compression and then to a lesser degree while being stored after packaging. This expansion, even when to a slight degree, results in a non-uniform sized product and is particularly bad in the case of applicator tampons where the applicator and tampon are each carefully sized to provide a balance between the force needed to expel the tampon in use and the frictional force needed to prevent the tampon from accidentally discharging from the applicator, both forces being functions of tampon size.
Accordingly, there is a need for a method of dimensionally stabilizing tampons.